Printing plate trimmer



2, 1955 L. F. COV'EN 2,714,242

PRINTING PLATE TRIMMER Filed May 4, 1950 5 Sheets-Sheet l IN V EN TOR.

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Aug. 2, 1955 F, COVEN 2,714,242

PRINTING PLATE TRIMMER Filed May 4, 1950 3 Sheets-Sheet 2 Fig. 4

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PRINTING PLATE TRIMMER Filed May 4, 1950 3 Sheets-Sheet 3 IN VEN TOR.

BY Lee CJWK) 45 UM], r a/w r hfiwg United grates Patent @thce 2,?14242 Patented Aug. 2, 1955 PRINTING PLATE TRMMER Lee F. Coven, Bratenahl, Ohio, assignor to The Cleveland Shopping News C0., Cleveland, Ohio, a corporation of Ohio Application May 4, 1950, Serial No. 159,905

3 Claims. (Cl. 2970) This invention relates to means for insuring uniformity in the distance between the printing matter on a tubular printing plate and the head and tail of such plate, so that there shall be perfect registration of the imprints by successively used plates, as in color printing. To this end the invention provides a machine adapted to receive the usual split tubular stereotype or electrotype and trim the slot between the head and tail of such printing plate accurately and uniformly with reference to a register mark on the plate. A succession of such trimmed plates, may be used one after another in printing on the same region of the paper to produce images in perfect registration.

Briefly, my invention provides a support for a tubular plate having a rough dividing slot therein; means for trimming such slot to a definite width throughout its length, and micrometer means for turning the plate on its axis in one direction or the other to cause the register mark thereon to register perfectly with a pointer which is fixed with reference to the path of the trimming mechanism. This provision for turnin the plate axially, and accurately positioning and holding it with reference to the trimming mechanism, insures the opposite walls of the trimmed slots, defining the head and tail of the plate, being exactly the same distance from the register mark on successively trimmed plates, so that perfect registration in the printing operation may be obtained.

My invention is illustrated in the drawings hereof and is hereinafter more fully described, and the essential novel features are summarized in the claims.

in the drawings, Fig. 1 is a perspective view illustrating the apparatus embodying the present invention; Fig. 2 is the perspective view of a portion of a printing plate prior to the trimming operation; Fig. 3 is a perspective View of a printing plate showing itS appearance at the completion f the trimming operation; Fig. 4 is a top plan view of the apparatus; Fig. 5 is a top plan view showing a portion of an end view of the portion of the apparatus as viewed from the line ii-S in Fig. 6; Fig. 9 is an end View of the apparatus as viewed from the line 99 on Fig. 5, and Fig. 10 is a section taken on a plane indicated by the line 1010 in Pig. 4.

As shown in Fig. l, the frame of my machine comprises a bed It) and the pair of spaced vertical standards 11 and 12 rising therefrom and providing bearings for a horizontal cylindrical plate-supporting member 24 The standard 11 is shown as a vertical plate having a circular hole 13 (Fig. 9) through it providing the bearing, while the standard 12. is shown as a box carrying a narrow upward extension 14 which supports a cylindrical bearing 15, coaxial with the bearing 13, and shown as having an end cap 16. Mounted in the bearing 15 is a shaft 21 (Fig. 4) having an annular end flange 22 which is attached by bolts 23 to one end of the cylindrical barrel Ed. The other end of this barrel extends into the bearing 13 in the standard 11 and has a head 24 fixed to it.

The end portion of the barrel 29 adjacent the standard 11 is formed with a cylindrical eniargement 25 terminating in a conical portion 26. The exterior diameter of the barrel 2% is substantially the same as the interior diameter of the stereotype plate A which, in use, is mounted on the barrel and jammed tight onto the conical portion 26. The plate may be readily slipped into position on the barrel by moving it axially over the bearing 15, the narrow support 14 being of less thickness than the ordinary slot :1 in the printing plate. v

To hold the plate in position snugly against the conical seat 26 i provide a sliding block 30 mounted in a slot 23 in the barrel 2%, and having an incline overhanging edge adapted to overhang a complementary beveled end edge of the tubular printing plate as appears in Fig. 6. As shown in Fig. 7, the block 30 has grooves at opposite sides occupied by ribs on a pair of bars 31 secured to the barrel Zii.

The clamping block St) is moved along its guideway by a screw 32 threaded in the flange 22 of the barrel extension. The screw may manipulate the clamping block in either direction and when the block is in clamping position, the screw may be locked by a jam nut 33.

The threaded flange 22 is located some distance back of the rib guide 31 and the screw is thus able to withdraw the block 39 completely off of the guide. In this withdrawn position, the block 3t may be swung on the extension of the screw as an axis down into the slot 28 of the supporting barrel to lie beneath the periphery of the barrel and thus not interfere with the sliding of the plate A along the barrel into active position and its subsequent removal from the barrel.

Secured to the top of the standard 11 and projecting longitudinally over the barrel enlargement 25 is a bar 40 carrying a pointer 41, the point of which is adapted to register with the register mark a on the tubular printing plate A.

When the plate A is slid manually into approximate position, the mark a more or less nearly registers with the pointer 41 as shown in Fig. 4. In such position, the cast slot a in the diametrically opposite side of the plate has its walls overhanging a materially wider slot 29 extending longitudinally along the lower portion of the barrel 20 as shown in Fig. 10.

To bring the register mark a accurately into registration with the pointer as indicated in Fig. 5, i use the micrometer adjustment heretofore mentioned and shown in Figs. 1, 5, 9 and 10, which will now be described.

Mounted on the end cap 24 of the horizontal barrel 20 is a cross bar 43, rigidly secured to the barrel as by bolts 44. On the standard 11 are a pair of blocks 45 in which are screwed screws 46, the lower ends of which bear against the cross bar 43. Each of these screws has a knurled knob 47 by which they may be turned by the operators fingers.

The loosening of one screw and tightening of the other turns the barrel 20 in one direction or the other a slight distance. The amount of turning is limited by stationary stop pins 48 carried by the standard 11 and adapted to be engaged by the cross bar 43.

The total possible swing of the barrel by the screws 46 is not enough to carry the edges of the plate A, at opposite sides of the cast slot 0, beyond the width of a slot 29 in the barrel 20, Fig. 10. Accordingly, whatever position the plate may be in, the slot to be trimmed is always well within the transverse area of the wider slot 29 so that in no case can the trimming mechanism engage the edges of such barrel slot. The limited adjustment, however, is sufiicient to bring the originally positioned plate from whatever its original position into accurate position for trimming, this original position being one where the original slot a aligns with the thin portion 14 of the standard 12.

The trimming mechanism comprises a pair of saws 50 mounted on the armature shaft 51 of a motor 52. This motor is carried by a horizontal plate 53 which has four supporting wheels 54 tracking on a pair of stationary parallel rails 55. The motor is supplied with electricity by a flexible two-conductor cable 56 controlled by a suitable switch 57.

When the switch 57 has been thrown to energize the motor, the latter with its carried saws 5% may be drawn by hand along the trackway and thus cause the saws to trim off the rough groove a (Fig. 2) and cut the accurate groove a (Fig. 3) in the plane of the saws. The saws mill the surfaces to provide the head and tail of the plate, and as this milling is effected at a time when the registration mark a on the plate is in registration with the pointer 41, it follows that the head and tail of all the plates treated will be identical distance from the registration mark. Accordingly, the images successively printed by such plates will be in accurate registration.

As the vertical plane in which the saws 50 lie should be very accurate with reference to the pointer 41, I provide means for adjusting laterally the position of the carriage 53 supporting the motor, thus enabling the accurate position of the saws to be efiected and maintained. This adjusting means comprises the lateral wheels 60 engaging the inner edges of the supporting rails 55. These wheels are carried by axles 61 journaled in blocks 62 which are laterally slidable in the motor plate 53, and are adjusted by screws 65 journaled in lugs 66 depending from the motor plate and threaded in the sliding blocks 62.

The adjustment described enables the carriage with its motor to be accurately positioned so that the saws will be accurately positioned, preferably on equal distances from the vertical plane passing through the point of the pointer 41. The wheels 54 are sufficiently shiftable axially on their supports to allow this ready adjustment by the guide wheels 60, which latter wheels take up any looseness and hold the saws exactly. in position.

It will be seen from the description given, and the illustrative views in the drawings, that I have provided a comparatively simple machine on which a printing plate of split tubular form of the proper diameter may be quickly mounted, tightly held, readily set to bring the controlling registration mark to a definite position, and then the slot defining the head and tail of the plate readily cut in accurate position with reference to the registration mark on the plate. Any number of plates of similar size may be mounted, one after the other, and trimmed so that each one in the press will produce an image exactly registering with the previous image or images.

The micrometer adjustment is very accurate and readily effected. The motor carriage is easily shiftable manually to perform the cutting operation but nevertheless snugly guided to avoid any looseness, thus maintaining the saws accurately in the position desired with reference to the pointer.

If the machine is to be adapted for plates of a different internal diameter, a plate carrying barrel of diameter corresponding thereto may be substituted by removing and replacing the bolts 23. Likewise, the saws may be readily shifted on the armature shaft and spaced exactly at the distance desired.

i claim:

1.111 a machine for trimming the slot of a tubular printing plate, the combination of a frame providing upright standards with a pair of bearings, a supporting barrel mounted in said bearings and adapted to carry the plate to be trimmed, means for guiding the plate slot into predetermined position on the barrel, a cone on the barrel to provide a stop for one end of the plate, a movable clamp on the barrel adapted to force the plate towards the cone and clamp the other end of the plate, trimming means supported in predetermined relation to said guide means for movement longitudinally of the plate to trim the slot therein, and micrometer means for turning the barrel on its axis slightly in either direction to position the slot in the plate with reference to the trimming means.

2. in a trimming device, the combination of a bed, a pair of spaced standards rising therefrom and each carrying a bearing, a horizontal barrel mounted in said bearings and adapted to carry a slotted tubular printing plate, one of the bearings having an external diameter no greater than that of the barrel, said bearing being carried by a narrow support no thicker than the slot in the plate, whereby the slotted plate may be slid over such bearing in predetermined position onto the barrel, means for holding the piate on the barrel, a traveling carriage carrying means in predetermined position relative to said narrow support to trim the slot in the plate, and means for turning the barrel to adjust the position of the plate relative to the trimming means.

3. in an apparatus for trimming the marginal edges of a dividing slot in a tubular printing plate in predetermined spaced relation from a fixed reference point on the plate the combination comprising, a pair of spaced end supports, a barrel rotatably journaled in the end sup ports and adapted to carry a slotted tubular printing plate in concentric relation thereon with the marginal edges of the slot disposed parallel to the barrel axis, a cutting device operably disposed for movement between the end supports adjacent the barrel and parallel to the barrel axis, said device having a pair of cutting edges whose cutting planes are parallel to each other and to the barrel axis and spaced from each other in a direction transverse to the barrel axis for trimming the marginal slot edges respectively of a mounted printing plate, means on one of said end supports for guiding a printing plate onto the barrel with the marginal slot edges of the plate in approximate alignment with the corresponding cutting edges of said cutting device.

References Cited in the file of this patent UNITED STATES PATENTS 243,745 Wilson July 5 1881 l,1l8,770 Higgins Nov. 24, 1914 1,253,705 Metzger Jan. 15, 1918 1,279,872 Jennings Sept. 24, 1918 2,149,025 Marion Feb. 28, 1939 2,268,078 McCordy Dec. 30, 1941 2,425,580 Tornberg et a1 Aug. 12, 1947 

